Automatic striking tool



2 Sheets-Sheet yl Nov, 30, i948..

Filed Sept. 19, 1945 Nov. 3G, i948. J. A. RAVELLA AUTOMATIC STRIKING TOOL Filed sept. 19, 1945' ZShe'etsaSheet 2 um .Dbuw DDDDDDDDDD a Patented Nov. 30, 1948 AUTOMATIC STRIKING TOOL Jean Adolphe Ravella, deceased, late of Lyon, Y France, by Valentine Auda, executrix, Lyon, France, assigner to Socit responsabilit limite Mermet & Virthner, Villeurbonne (Rhone), France, a French company Application September 19, 1945, Serial No. 617,281 In France February 26, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires February 26, 1963 14 Claims. (Cl. Sli-52.35)

This invention refers to a tool comprising an inner spring loaded hammer so disposed that by pressing this tool against an object a blow is delivered on a striking head forming the working end of the tool. This striking head may be, for instance, a conical center-point adapted to strike a center-mark, an engraving punch, a hollow punch or any other type of elementary tool acting under the action of a blow.

The known automatic tools of the kind above referred to generally comprise a movable outer part, such as the handle proper or a part thereof, which may be lowered with respect to the other portions of the tool against the action of an inner spring resting against an inner movable hammer retained by appropriate pawls.` When the spring is sufficiently compressed, the pawls are automatically disengaged and the hammer strikes the striking head of the tool.

A rst object of the invention isgto provide an automatic tool of the kind above referred to which will comprise no pivoted pawl able to wear off too rapidly and difficult to house within a handle of normal design.

Another object of the invention is an automatic striking tool for hand purposes, wherein the hammer may be heavy enough to deliver a strong blow under theaction of a spring of average strength, which the operatormayy compress without exerting an exaggerated effort.

A yfurther yobject of the invention is an automatic tool of the kind above referred to, wherein the hammer is retained against the action of the spring by balls movable in holes in a fixed wall having a lesser thickness than the diameter of the balls, such balls co-acting with depressions provided in the hammer and in a slidable retaining part, in such a wat7 that in the free state the balls are maintained in the depressions of the hammer by the plain portion of the retaining part, while at the end of the stroke of the rnovable handle the retaining part is moved, whereby the balls may penetrate into its depressions and become disengaged from the hammer which is thus freed.

In the annexed drawings:

Fig. 1 is a general longitudinal section of an automatic striking tool according to this invention, in the free state. K

Fig. 2 is a similar section showing the parts when the handle hasv been depressed but before the hammer is freed.

Fig. 'similarly shows the parts when the blow has been delivered.

Fig. 4 is'an enlarged detailed section showing a ball when the hammer becomes free.

Fig. 5 is a partial View illustrating the upper end of the tool with the scale indicating the adjustment of the striking spring.

Fig. 6 shows in longitudinal section a modified construction.

The tool illustrated in Figs. 1 to 5 comprises an outer body or handle I which houses a slidable socket 2 provided with a longitudinal groove 3 (1o-'operating with the end of a screw 4 fixed to handle I. Groove 3 is limited in' length and screw 4 therefore acts as a slidable key limiting the longitudinal motion of socket 2 with respect to handle I.

The lower end of socket 2 is open and is adapted to receive removable points or punches, such as the conical center point 5, such points or punches being provided with a shoulder B retained with a given amount of longitudinal play between an inner shoulder 'I of socket 2 and an end ring 3. Point 5 is 'passed through ring 8, as shown. It is also tobe noted that shoulder 6 is discontinuous and comprises a notch 9 which is engaged by a projection ID of ring 8 in such a way that point 5 is prevented from rotating with respect to ring 8 when ring 8 is screwed up.

The hammer II is a cylindrical body sliding within the upper portion of socket 2 and adapted tostrike the upper end of center point 5. The upper end of hammer II above socket 2 is hollow and houses the lower end of a strong striking spring I2 the upperl end of which abuts against a cap I3 screwed on'the upper end of a sleeve It, itself screwed on the upper end of body I. As shown, the upper edge of hammer Il is turned outwardly as indicated at I5 and its downward stroke is limited by an inner shoulder I6 provided within sleeve I4.

Another spring Il, of much less strength than spring I2, abuts against the upper end of socket 2 and under shoulder I6, thus tending to lower socket 2 with respect to body I or vice versa, this motion being limited by screw Il and groove 3 as above explained. A

There is disposed between socket 2 and body I a slidable ring I8 resting on a light spring I9 which in turn rests on an inner shoulder forming the lower part 20 of body I. The lower part of ring I8 has an inner diameter substantially equal to the outer diameter of socket 2, while its upper part is somewhat larger and accommodates the flanged upper end ZI of socket 2.

. The wall of socket 2 is provided with a number of holes 22 adapted to house balls 23 which,

being larger in diameter than the thickness of this wall,v project inwardly into a circular groove 24 provided infliammer lI, when the: tool is at rest (position of Fig.` 1)". It is to be noted that balls 23 are radially retained by the slidable ring I8. Hammer Il is thus longitudinally keyed with respect to socket 2. provided with an internal groove 2.5 which is normally situated above balls 23,-an zl-when`- ring t8 is lowered against theV action offspring." F92 groove 25 comes in front ofball's Zhiwhichbe come free to move radially, wherebylhamrner II` is freed.

The operation is as follows:Y l

When the tool is not in use (Fig. 1) the-'striking spring I2 maintains the flangedI upper.. edge I5 of hammer Ii against the inner shoulder Iii,v off sleeve I4. Spring II has lowered socket 2 with respect to body I. Ring I8 is maintained byI spring I9 at its uppermost position for which its lowerfinternal .diameter abuts against theflanged upper endf. oils'ofcket 2". 1 Groove 25 isf thuswell above balls '23'whichactaskeysinserted between socket il andi hammer Ill to prevent any respective longitudinal motion' of these parts. Itwill be noted that the Yupward.Iriov-emen't ofV bodyv I'. with respect to socket 2 is limited by the angedzupper end-.ILS of hammer lfi` which abuts againstshoulder IGasabove explained. .Point `5` is at' any intermediate position 'between4 the eXtreme: positions determined. by Athe longitudinal. play of` shoulder @between ring BY-and shoulder 'I.

lfoin'tV 5 is placedlon an'v appropriate? piece of work- 2i-"(Fig.\ 2) and th'evhandlel otthetooll is lowered, such handle being formed otbody IA with sleeve' mand-cap I3` `Shoulder @of point 5 comes intooontact with` shoulder .1 Yand springs Ir-Iaand I2 are'z thereafter simultaneously` compressed. .the rst onebetween shoulder IIS and the flangedr upper .endl 2Il of socket 2,.-the secondv one lbetween capY I3 and. hammer II, the latter being longitudinally keyed by balls 23dv with socket 2 which acts as a iixed ballV supportingv partition, since it rests on the work. l

The lower end of4 sleeve I4 comes into contact with/the upper end ovring I8- (Fig. 2) A`and lowers the same-against .the action oispririgv |19... .Groove 25 thus moves towards balls 23 untill the latter may penetrate into the same underthe action cfa-'the edges-of vgroove 24 (Fig.r2 shows thesparts just before thismomentl 'Hammer II then becomes-rtree` tofmove under the actionof-sprin-g I21 and -it delivers a strong blow on'v theupper end ofpoint 5 which penetrates into the work' 25 (Figs. 3 and 4) y It will be observedthat owingv to the axial play of the shoulder (i` of point 5y between shoulder I and ring 8, the blow is not transmitted toY socket 2. Point 5 is quite independentffrom the other parts of the tooland -the operator does not feel the blow.

` `When the handle is permitted to raise again, balls 23 are at rst retained in groove 25 by the ungrooved portion of hammer `I I and they axially connect ring I8 and socket .2 with eachother. Ring |18 therefore does not move while body l and sleeve I4 are raised bythe combined action of springs I2 and Il. Spring Il?l remains inthe compressed state.

WWhen the shoulder I6 of sleeve I4 comesinto contact with the flanged end? I5' ofA hammer I'I', spring I-2 is rendered inactive and hammer Il is raised by spring II'Il together with sleeve I4.

yWhen screw 4 reachesther upper end of groove 3, the circular groove 24 of hammer II1.comesin But ring:- I@ isnalso:

vHammer II is again locked with socket 2 and the parts are in the position of Fig. 1.

The'blow delivered by hammer l i may be varied by screwing or unscrewing cap I3 on sleeve I4, the latter being preferably provided with graduations 2.1 (Fig. 5l- V,Spring I2 may also be changed at will by'rem'ovingsaid cap.

f .Owing to. the small radial dimension of the ball-lock, it is possible to house the same within anormaltool handle without having to reduce tfl'ie'ed'iameter of the hammer and consequently its mass. They improved tool besides comprises no pivoted pawl liable to become ineffective under the action of wear; balls 23 remain spheric and the balldock operates satisfactorily even after prolonged use. Y,

Instead' ofL.-t-he conical center point 5; the tool described mayreceive punches, for instance engraving punches for jewelry or `for marking mechanical parts\vithout the need of an ordinary hammer. Due to projectionl Ill (Figs. 2 and 3) the:V punch usedA is preventednfrom` rotating and itsl position withl respect to screw 4 remains invariable, which is essential in the case of an engraving punch. .Point 5' may also be replaced by any elementary tool actuatable by a blow, for example, by a hollow-punch', a chisel, etc. The improved tool may even be usedv as a hammer, for instance f'ornailing, point 5i being in such a case replaced by a flat-ended rod which is pressed against the nailihead.

InI the modified. construction of Fig. 6, sleeve I4 andl capk I-3 of Figs. 1 to 6 are-formed of one and thesame part I'4a. Shoulder I6 is formed at the lower-end of a sleeve I6'a loose withinv part If4a, saidsleeve receiving the upward pressure of spring' IT; The. operation remains the same, but during theupward stroke' of .the-handle spring I2 must becomewholly unloaded before sleeve I'a may begin to raise under.' the actionf of spring. I'I and! to liftshammer I-I. The'length ofv spring I2 in -tlie free state'has; therefore' to be exactly `determined and-thel force of' the blow can only be variedby changing said'Y spring i12".

It -is claimed 1. An automatic striking tool othe character described comprising a body Vhaving. abutments at its upper and' lower ends; astriking head ver'- tically slidabley at ther lower end of saidf body; averticall membernrestin'g .on .said striking head andv vertically slidable therewith. in said body, said member` having holes; balls inA the: holes of said member, said balls being largerr in; diameter than. :the tl'ii'ckness,disaid member; a hammer adapted' toverti'cally slide' againstoneiace of lsaid member and" to strike said striking-head', said hammerhaving groove adaptedto co-act with said'lballs at the uppermost position of said hammer to'longitudinally locksaid hammer tosaid member; a balli-retainingpart slidable against the face of said member opposed to said hammer, said ball-retaining ,part having depressions adapted to co-act with said balls at the lowermost position ofsaid ball-'retaining part to unlock said hammer from said member ;A spring meansinterposed between the member and' the-abutment at the upper end of said-body and adapted toact downwardly on ysaid hammer' whensaid: -body is lowered with respect to said striking head; other spring mea-ns interposed between: -th'efl abutment at the lower end of the body andzthe'ball-retaine ing part to maintain saidball-retaining part at its uppermost position in which same prevents said balls from freeing said hammer under the action of said first-named spring means;"and means on the body to lower said ball-retaining part against the actionof said second-named spring means to cause the depressions offsaid part to co-act with said balls atfthe end of the downward stroke of said body withr'espect to said striking head; and means for yieldably urging the hammer into Contact with the striking head.

2. In an automatic striking tool as claimed Yin claim 1, said member being tubular and said hammer being formed as a cylinder slidable therein.

3. In an automatic striking tool as claimed in claim l, said ball-retaining part being tubular, said member being also tubular and slidable in said tubular ball-retaining part, and saidhammer being formed as a cylinder slidable in said tubular member, v l

4. In an automatic striking tool as claimed in claim l, said body being hollow, said ball-retaining part being tubular and slidable longitudinally in said body, said member being also tubular and slidable in said tubular ball-retaining part. and ,5

said hammer being formed as a cylinder slidable in said tubular member.

5. An automatic striking tool of the character described comprising a tubular body; a member longitudinally slidable in said tubular body, said y member having a circular row of holes and being spaced from said body inthe vicinity of said row of holes; balls inthe holes of said member, said balls being larger in diameter than the thickness of said member; a slidable striking head at the lower end of said member; a cylindrical hammer slidable in said member, said hammer having a circular groove adapted to receive said balls at the uppermost position of said hammer within said member to lock said hammer to said member; a tubular ball-retaining part slidable in the annular space between said member and said body to urge said balls into said groove, said part having an inner `circular groove adapted to co-act with said balls at the lowermost position of said part with respect to said member to unlock said cylindrical hammer from said member; a cap at the upper end of said tubular body; spring means interposed between said cap and said cylindrical hammer and adapted to act downwardly on said hammer when said body is lowered with respect to said member; other spring means interposed between the lower end of said tubular body and said ball-retaining part to yieldably maintain said part at its uppermost position in which it prevents said balls from freeing said hammer under the action of said first-named spring means; and means on the body to lower said ball-retaining part against the action of said other spring means t0 cause the inner groove of said part to co-act with said balls at the end of the downward stroke of said tubular body with respect to said member.

6. In an automatic striking tool as claimed in claim 5, said means to lower said tubular ballretaining pa-rt consisting of an inner abutment formed on said tubular body.

7. In an automatic striking tool as claimed in claim 5, said cylindrical hammer being outwardly flanged at its upper end and said tubular body being formed with an inner shoulder co-acting with the flanged end or" said hammer to limit the downward motion of said hammer with respect to said tubular body under the action of said rstnamed spring means when said body is in the tubular body under the actionof said first-named spring means when said body is in'the vicinity of its uppermost position with respect to said tubular member; and said cap-being adjustable longitudinally on said tubular body to permit of adjusting the blow of said hammer on said striking head. f

v9. An automatic striking tool of the character described comprising a tubular body; a tubular .member longitudinally slidable in said tubular body, said member having a circular row of holes and'being spaced from said body in the vicinity of said row of holes; balls in the holes of said tubular member, said balls being larger in diameter than the' thickness of said tubular member; a striking head axially slidable within the lower end of said tubular member; means to limit the sliding movement of said striking head with respect to said tubular mem-ber; a cylindrical hammer slidable in said tubular member, said hammer having a circular groove adapted to receive said balls at the uppermost position of said hammer within said tubular member to lock said ham mer to said member; a tubular ballretaining part slidable in the annular space between said tubular member and said body to urge said balls into f said groove, ysaid part having an inner circular groove adaptedto coeact with said balls at the lowermost position of said part with respect to said tubular member to unlock said cylindical hammer from said member; a cap at the upper end of said tubular body; spring means interposed between said cap and said cylindrical hammer and adapted to act downwardly on said hammer when said body is lowered with respect to said tubular member; other spring means interposed between the lower end of said tubular body and said tubular ballretaining part to yieldably maintain said part at its uppermost position in which it prevents said balls from freeing said hammer under the action of said first-named spring means; and means on the body to lower said tubular ball-retaining part against the action of said other spring means to cause the inner groove of said part to co-act with said balls at the end ci the downward stroke of said tubular body with respect to said tubular member.

10. In an automatic striking tool as claimed in claim 9, means on the member adapted to prevent said striking head from rotating with respect to said tubular member.

11. In an automatic striking tool as claimed in claim 9, means to prevent said tubular member from rotating with respect to said body.

12. In an automatic striking tool as claimed in claim l1, said cylindrical hammer being outwardly flanged at its upper end and said tubular body being formed with an inner shoulder co-acting with the flanged end of said hammer to limit the downward motion of said hammer with respect to said tubular body under the action of said first-named spring means when said body is in the vicinity of its uppermost position with respect to said tubular member.

13. In an automatic striking tool as claimed in claim 11 said cylindrical hammer being outwardly flanged at its upper end; said tubular body being 7 formed. witli- .am inner shoulder: emaetngowith the flanged end of said hammer tmlmitihadwnward'motions oli said'.=hammer with: resnet. tlo .said iru'bulan vbodyaunder.'the actionAoi'saidffrsti-named spningsmeansf when said; bodyv is; in; the vicinity ofsiitsruppermosh .position witlrrespeoiz torsaid tubular member and; said; can` beingrxadiustalhe longitudinally on -saidiltubularbody tm permit: ad-

justment'iofgthe iorceof Vthebloyit of hammer ,onsaid striking: head; y M Anautomatio. strik-ingr tool; oi character desenilned; comprising atubularbody;v a member: longitudinally sliidable in?. saldi. Vtubular body, said memberihaving: acircular: romwofholes and being spaced from said body in the; vininity of' said row of holes; ballsin the holesofisasidtubular member,A said balls being larger irl-diam- -eter'than the Ithickness of said member; a-strik- .ingf head at vthelower endof -saidtubular memberge.l cylndricalhammer slidable in said tubular member, saidhammer having a circular groove adapted to receive said balls at the uppermost position of'said. hammer within-saidvtubularfmember tolockf said hammer to saidnmember; a tubular ball-retaining part slidable in .the `annular spaceibetween .said-tubularmemberlandsaicfbody -courge-said balls into said .groove said- :part having an inner circular groove adapted to` co-act with said balls at the lowermost position of said part with respect to said tubular member to unlock said cylindrical hammer from said member; a .capi at the upper vend of said tubular body; springwmeans interposed' between 4said can and said? cylindrical hammer and adapted to-act downwardly on said hammer when said body is lowered with respect tov said tubular member; other Cil vspring meansinternosed'between the lower end off :s2dr tubularirbody and said tubular ball-re- ;ta-ininggartto; elastically malin-,ain said part at itsuppermost-position in which it' prevents said lbaljlsffrxom-I vfreeing said hammer under ,the action offzsaiderst-.named spring, means; means on the body to;,lower said tubular ball-retaining part ig-.ailllsitthe actionv of said other spring,r means to .caalaeltheinner groove of said part toco-act with Saddam-11s at.. the end of the downward stroke of sadntubula-i?bodv'witnrespeet to said tubular membmgurther spring mea-nsinterposed betmenfsafidrtubular 'member and said tubular body minimo-.Saldi bodytodts uppermost position with remonta saidmember; and means` onl .the body ,and'mmher toglimit therespeotive longitudinal Vmollimzr QE saidtubular body and of said tubular member.

, VALENTINE AUDA.

Ear-eeuwige of the Estate of Jean Adolphe Busalla,

" rDeceased'.

Y f REFERENCES: CITED I hef .ol1o,wing references are. of ,record in the lille `of this patent:

UNITED STATESPATENTS 

